1. Field of the Invention
The present invention relates to a digital camera of which operation sequence is changed in accordance with a property of battery.
2. Description of the Prior Arts
A digital camera is provided with an imaging device (for example a CCD image sensor), an A/D converter, an image processing circuit, an image memory, a diaphragm mechanism, a shutter mechanism, and so forth. The imaging device converts an optical image to an image signal. The A/D converter converts the image signal to a digital image signal. The image processing circuit carries out gradation correction, color correction, contour enhancement, sharpness processing, image cropping, and so forth. And the digital camera has a zoom lens, an electronic viewfinder, and a flash device. This electric viewfinder is constituted of a liquid crystal display panel (LCD) of a transmission type and a lamp for lighting the LCD panel.
In the taking mode, the digital image signal outputted from the image processing circuit is sent to the LCD panel to display a moving image in taking operation. The moving image is a rough image made of thinned pixels. When the shutter button is depressed, a fine still image having large number of pixels is stored in a memory medium (a memory card, for instance). And when the display mode is selected, a still image is read from the memory medium to be displayed on the LCD panel.
A primary battery or a secondary battery is loaded into the digital camera, by which the above electric circuit, the flash device, the electric viewfinder and the like are driven. Particularly the electric viewfinder and the flash device have large power consumption. When the battery is consumed while using the digital camera, the digital camera stops operating in the middle of operation.
So as to prevent the digital camera from stopping its operation, various measures have been taken. For instance, the following methods are known: one for changing charging voltage of a flash device in accordance with a type of a battery (JPA No.2000-241860), and the other for judging whether to shift to the display mode or not in accordance with a type of a battery (JPANo.2000-261975). And it is also known the method for limiting the display mode or the flash taking in accordance with the measured voltage of a battery, and for changing a set time until the power is automatically turned off (JPA No.2000-253303).
However, all measures mentioned above limit selectable operation modes in accordance with a type of a battery or a remaining amount of a battery. It is not possible, for example, to select the display mode and the flash taking in case of small capacity of power supply. This may cause a user to find it hard to use the digital camera.